As to the Opus Dei:
http://freedomofmind.com/resourcecenter/groups/o/opus/
http://www.mond.priv.at/opus.dei/
People who leave the Opus Dei complain in pretty much the same terms you Jehovah's witnesses complain about the Watchtower.
in Catholic churches where they don't have those lovely and convenient 'kneeling' pads attached to the pews, can one bring their own kneeling pad???
In my experience, yes, you can. I don't think there is a policy on that.
As to "poor churches" I think churches in the United States are not what I have in mind. Think what churches could be like in Africa. Sometimes Kingdom Halls are pretty in comparison, particularly because they are clean.
I must say, it appears that the Catholic Church has handled its scandal far better than the Watchtower Society, in that the Catholic Church appears to be taking positive steps to prevent such abuses in the future.
Sometimes they do, sometimes they don't. I was never abused by any of the many priests I met. I did hear that some of my friends said one priest "used to touch" them, meaning he used to manipulate children's penises. What the church did with Marcial Maciel and the Legion of Christ was awful (https://secure.wikimedia.org/wikipedia/en/wiki/Marcial_Maciel).
On the other hand, there are also priests who won't tolerate this and won't do it. One of my fond memories of my childhood was the Italian father that came to our parish. He was fond of me and wanted to teach me Italian, an offer I should have taken. This priest was a very handsome man, tall and very strong, and with deep blue eyes. I know my mother fancied him . In what became one of the juiciest pieces of gossip of the time, one of the women in the parish came to his office, took her clothes off, and then asked to be "made his woman". The father removed his belt, yes, but it was to beat her with it and pushed her out of the office. Then he threw his clothes to her. The parish lost one of the faithful workers, indeed. After that, the man won everyone's respect, however.
I must say that same parish saw many priests "step out" with women. Most priests married the women. In one case, the woman didn't want to marry him.
Years later, I saw him again. He was a missionary abroad. He was very much tanned, he looked a lot weaker, and much older. His beard was now white, but he was still the same religious man.
